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Thermally activated breakdown in a simple polymer model.

S Fugmann¹, I M Sokolov

¹Institut für Physik, Humboldt-Universität zu Berlin, Newtonstrasse 15, D-12489 Berlin, Germany.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|April 7, 2010

Summary

This summary is machine-generated.

This study models polymer chain fragmentation, finding that bond breaking times depend on chain length and bond location. Free chain ends exhibit the fastest fragmentation rates.

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Area of Science:

Polymer Physics
Chemical Kinetics
Statistical Mechanics

Background:

Homopolymer chain fragmentation is crucial for understanding polymer degradation and material properties.
Previous models often simplify bond breaking dynamics, necessitating a more detailed approach.

Purpose of the Study:

To model the thermally activated fragmentation of a homopolymer chain.
To investigate the influence of chain length and bond location on bond activation times.
To compare theoretical predictions with simulation results.

Main Methods:

Utilizing Rouse dynamics for intact chain behavior.
Treating bond breakdown as a first passage problem over an energy barrier.
Applying the Wilemski-Fixman approximation to calculate bond activation times.
Conducting Brownian dynamics simulations for validation.

Main Results:

Calculated activation times for individual bonds in free and grafted homopolymer chains.
Demonstrated a critical dependence of activation times on chain length and bond position.
Observed a minimum activation time at the free chain ends.
Found qualitative agreement between theoretical predictions and simulation data.

Conclusions:

The Wilemski-Fixman approximation provides a robust framework for modeling polymer fragmentation.
Chain end effects significantly influence the rate of polymer chain fragmentation.
Brownian dynamics simulations support the theoretical model's predictions.